A belt type continuously variable transmission transmits power using a belt wound around a drive pulley (primary pulley) and a driven pulley (secondary pulley).
When a vehicle installed with this belt type continuously variable transmission decelerates rapidly, a downshift is performed rapidly in accordance with the deceleration to secure a restarting ability following the deceleration.
When a downshift is performed rapidly in this manner, an oil pressure of the drive pulley decreases rapidly, and as a result, a gripping force of the belt in relation to the drive pulley decreases transiently. In this condition, vehicle wheels may lock and the belt may slip due to an increase in inertial torque during the downshift or the like.
JP11-13876A discloses a control device for a continuously variable transmission which prevents this type of belt slippage from occurring by performing rapid deceleration gear ratio fixing control during rapid deceleration. In this control, a gear ratio is fixed at a predetermined High side gear ratio when the deceleration reaches or exceeds a predetermined value, and as a result, the oil pressure of the drive pulley is secured.